A. Field of Invention
This invention pertains to a window treatment operated by a cord, wherein a disabling device is provided to disable the window treatment if the cord is not tensioned properly. The device includes one or more gears engaged by the cord and blocked from rotation when the cord is not tensioned properly.
B. Description of the Prior Art
In the present application the term ‘window treatment’ refers to an apparatus for selectively covering a door, a window or other architectural feature in a building. Typical window treatments include window shades or blinds, venetian blinds, roman shades, vertical blinds, pleated blinds, and so. Window treatments can be operated either manually, using one or more cord, or automatically using an electric motor to activate the shade and a remote controller coupled to the electric motor either via a wired or wireless connection. The remote controller may respond to commands from a user or may operate autonomously. However, automatic window treatments are very expensive and complex, and by and large, the majority of window treatments are operated manually. Most of these latter types of window treatment include a built-in control mechanism that is used to operate the window treatment, e.g., raise or lower a fabric sheet, a plurality of slats, etc., with an elongated member such as a cord engaging the control mechanism. For example, the control mechanism may be a clutch such as one manufactured by Rollease, Inc. of Stamford, Conn.
It has been found that it is advantageous to tension the cord after the window treatment has been installed, and to disable the control mechanism and immobilize the cord if the free portion of the cord is not tensioned properly, but it is left loose adjacent to the window treatment. Mechanisms for disabling window treatment control mechanisms have been previously proposed, however, they were not found to be convenient to make and are not always effective.